Cut Smart recently dealt with this question:
Does anybody out there know how to create a perfect joint where radii come into one another on a steel rule die? We have more than one customer that insists that their radius cornered gaskets be run with a common cut in both directions to save material. On the other hand we have a diemaker that insists that he must have a double knife in order to put in the radius corners. There must be a way but we’re diecutters not diemakers and have no idea how. Should we find a new diemaker or is there some information out there they could use? Thanks!
- For the common application where a steel rule die will be used in some type of flatbed cutting operation, the best answer we can give is to use Rule Connectors - A.K.A. - Rule Joiners - These are a love/hate product. Some people swear by them; others swear at them! Rule Connectors are a solid steel machined punch which replaces the regular steel rule at tough to make joints. Rule Connectors typically replace normal rule where rules meet at a radius corner.
The Plus Side is this -
- At the point where most diemakers have an major problem making a joint that works and is accurate, especially in tough materials, the rule is replaced by a virtually indestructible piece of machined steel that is perfect. The joints are moved to an easier and more desirable location usually on a straight-away and the problem is solved.
- They are readily available, in a variety of different radii.
- The Custom possibilities are endless.
There are two main drawbacks -
- One is how the rule and punch is installed. Rule Connectors typically have "V" notched ends that join rule to the punch. If you do not cut the rule to the right size or the bevel on your rule is off-centered, you will pull your hair out trying to get the tool to work properly. However, if it is installed correctly, you will have virtually no spaces or natural nicks in the rule pattern. When you put it together right, it works great, especially on materials that love to separate rule.
- The other drawback is the cost of the Rule Connectors. They cost roughly $20 to $30 (USD) each. Most of the time the cost can be justified by eliminating downtime, rule repairs and material waste. If you have a small run, the cost may be prohibitive.
To answer the question more pointedly –
The diemaker may be right! Even though there are rule joiners on the market, you will leave yourself open for more actual natural nicks than if you had allowed for space between your cavities and had made only one or two natural nicks in each cavity. Depending on your customer’s final product, this may be a big factor when selling the job in the first place.
Other answers in a case like this one are numerous - Could the product be more easily cut in a rotary application where a solid machined or chemically etched tool may be of use? No joints here! Also it may be worth thinking about a fully machined punch or die that actually outlines and cuts the entire image without any joints. More expensive, but in some cases that doesn’t matter at all. Have you thought about, for short runs, laser cutting, waterjet cutting or CNC Knife cutting machine production? All of these are methods that are being used and are working well in the right situations.
Rule joiners are not new to the market. As is the case in many situations, the usual for one manufacturer is the unusual for the next. Good luck in all your cutting adventures.
Please contact Cut Smart if you would like more information on this subject.
© 2004 Cut Smart Engineering & Manufacturing, Inc. All rights reserved.
